Generally speaking, a stator is fitted around a tube, which is located onto a center of a base, such that the stator is located onto the base. The tube is a hollow cylinder and has at least one bearing fitted therein. A rotor is extended through by a shaft to connect to the shaft, so the rotor is fixedly located onto the base and corresponding to the stator. The stator is fitted around the tube or located onto the base by gluing.
However, using glue to connect the stator to tube or the base has the following disadvantages: (1) additional labor time is required in the whole manufacturing process, causing higher manufacturing costs, and it is apt to glue-overflowing; (2) when one component, such as the stator, is broken, the whole structure is needed to be substituted, causing wasting much resources; and (3) the stator is heated in operation and apt to slide when being connected by gluing.